Sound spectrogram of 2 s of courtship at 23°C (from the 11 s recording by K. N. Prestwich above). The soft, nearly continuous, shuffling sounds have a dominant frequency similar to the calling song (4.7 kHz) as do the two-pulse chirps with strong harmonics that are the loudest sounds. In contrast, the brief (10 ms), periodic ticks have their strongest frequencies at about 12 kHz. When courting a female, some males omit the two-pulse chirps in the terminal phase of a successful courtship; others do not.

Click on spectrogram to hear graphed song.

G. pennsylvanicus and G. veletis cannot be reliably distinguished
by either song or external morphology (although in some localities the ovipositors
of G. pennsylvanicus average substantially longer than those of G.
veletis). However, G. veletis overwinters as mid-to-late instar juveniles,
whereas G. pennsylvanicus overwinters in the egg stage. Both species have
only one generation per year. Consequently, G. pennsylvanicus adults are
most abundant in fall and G. veletis adults are most abundant in spring.
In all localities where the species have been studied, a few adults of the two
species occur together in midsummer.